Analytical Model for Redistribution Profile of Ion-Implanted Impurities During Solid-Phase Epitaxy

We evaluated the redistribution profiles of ion-implanted impurities during solid-phase epitaxy using Rutherford backscattering spectrometry (RBS). RBS data revealed that the As concentration changes only near the moving amorphous/crystal interface. We derived an analytical model for the redistribution profiles using a segregation coefficient m between amorphous and crystalline Si, introduced a parameter of reaction length l that is the distance where impurities were exchanged, and obtained good agreement with experimental data with an m value of 3 and an l value of 1 nm for As. Furthermore, we applied our model to P and B redistribution profiles and obtained good agreement with corresponding m value of 4 and l value of 1 nm for P and m value of 0.3 and l value of 1 nm for B     

Investigation of PSt-MWCNT concentration on epoxyacrylate photopolymerization and conductivity of polymer films

Photopolymerization kinetics and conductivity changes of epoxyacrylate composites for various loading modified PSt-MWCNT weight fractions changing from 0.0025 to 0.2 wt.% were evaluated by performing photo differential scanning calorimetry (photo-DSC) and four point conductivity measurements. 0.2% PSt-MWCNT additive polymeric films had their electrical conductivity boosted by 6% more than non-additive polymeric films.     

Current-mode level restoration: circuit for multi-valued logic

The multi-valued logic circuits provide very small chip size, higher speed, and a small number of interconnections. However, the main drawback of these circuits is the lower noise margin and it is necessary to restore the nominal levels of the signal after a certain number of cascaded stages. A new current-mode CMOS restoration circuit is presented and evaluated.     

One‐step synthesis of triarm block copolymers via simultaneous reversible‐addition fragmentation chain transfer and ring‐opening polymerization

One‐step synthesis of star copolymers by reversible addition–fragmentation chain transfer (RAFT) and ring‐opening polymerization (ROP) by using a novel dual initiator is reported. Triarm block copolymers comprising one polystyrene (or polyacrylamide) arm and two poly(β‐butyrolactone) arms were synthesized in one‐step by simultaneous RAFT polymerization of styrene (St) (or acrylamide, designated as AAm) and ROP of β‐butyrolactone (BL) in the presence of a novel trifunctional initiator, 1,2‐propanediol ethyl xanthogenate (RAFT‐ROP agent). This dual initiator was obtained through the reaction of 3‐chloro‐1,2‐propanediol with the potassium salt of ethyl xanthogenate. The principal parameters such as monomer concentration, initiator concentration, and polymerization time that affect the one‐step polymerization reaction were evaluated. The characterization of the products was achieved using Fourier‐transform infrared spectroscopy (FTIR), ¹H‐nuclear magnetic resonance (¹H‐NMR), ¹³C‐nuclear magnetic resonance (¹³C‐NMR), Gas chromatography–mass spectrometry (GC–MS), gel‐permeation chromatography (GPC), thermogravimetric analysis (TGA), and fractional precipitation (γ) techniques. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Transferrin-Decorated Niosomes with Integrated InP/ZnS Quantum Dots and Magnetic Iron Oxide Nanoparticles: Dual Targeting and Imaging of Glioma

The development of multifunctional nanoscale systems that can mediate efficient tumor targeting, together with high cellular internalization, is crucial for the diagnosis of glioma. The combination of imaging agents into one platform provides dual imaging and allows further surface modification with targeting ligands for specific glioma detection. Herein, transferrin (Tf)-decorated niosomes with integrated magnetic iron oxide nanoparticles (MIONs) and quantum dots (QDs) were formulated (PEGNIO/QDs/MIONs/Tf) for efficient imaging of glioma, supported by magnetic and active targeting. Transmission electron microscopy confirmed the complete co-encapsulation of MIONs and QDs in the niosomes. Flow cytometry analysis demonstrated enhanced cellular uptake of the niosomal formulation by glioma cells. In vitro imaging studies showed that PEGNIO/QDs/MIONs/Tf produces an obvious negative-contrast enhancement effect on glioma cells by magnetic resonance imaging (MRI) and also improved fluorescence intensity under fluorescence microscopy. This novel platform represents the first niosome-based system which combines magnetic nanoparticles and QDs, and has application potential in dual-targeted imaging of glioma.     

A paleoenvironmental test of the Messinian Salinity Crisis using Miocene–Pliocene clays in the Adana Basin, Southern Turkey

The Messinian Salinity Crisis is an important paleooceanographic event around the Mediterranean area. Due to the collision of the North African Plate with the European Plate the Mediterranean area lost its connection to the Atlantic. The Mediterranean sea became shallower; the biota changed and thick evaporitic beds were formed.Paleoenvironmental characteristics of Upper Miocene–Pliocene units of the Adana Basin have been explained by using clay mineralogy analysis. For this purpose, X-ray diffraction studies were carried out on 85 samples collected.In the Upper Miocene–Pliocene sequence high kaolinite content of siltstone, claystone, sandstone, marl and silty marl of the Tortonian units indicates a humid climate. During the Messinian, the content of kaolinite decreased, indicating that the area was arid. After the Messinian, the kaolinite content increased again, showing that environmental conditions of the area became humid again.Correlations of illite and smectite content indicate humidity and temperature of the paleoenvironment, according to previous studies carried out in sequences related to the Messinian Salinity Crisis. The illite content increased in the Tortonian, diminished during the Messinian and increased again in the Pliocene while the smectite ratio showed the opposite trend. In this study, illite ratio is increased during Tortonian and Messinian and decreased in Pliocene while smectite ratio is increased from Tortonian to Pliocene.     

Filtration characteristics of aluminium hydroxide mixtures (alumina hydrates)

The specific cake resistance of the alumina hydrates obtained from sodium aluminate solutions was investigated against the caustic ratio, ageing and filtration pressure using a laboratory test filter at constant pressure filtration conditions. The alumina hydrate product was produced from sodium aluminate solutions by seeding the aluminium hydroxide crystals of definite size distribution at constant solution temperature. The specific cake resistance was found to increase with the caustic ratio and filtration pressure and to decrease with the ageing of alumina hydrates in aluminate solutions.